Apparatus for forming sheet metal



Feb. 20, 1940. v H. E. GUERIN 2,190,659

APPARATUS FOR FORMING SHEET METAL Original Filed Sept. 9, 1955 2 Sheets-Sheet 1 Q Q Ill-II Hummu- INVENTOR HENRY 4S. GUER/N 5 Y FEW Feb. 20, 1940.

HE. GUERIN APPARATUS FOR FORMING SHEET METAL Original Filed Sept. 9, 1935 z'sh ts-sheet 2 w NE. 4 w n a w A 7T0 RNEY.

Patented Feb. 20, 1940 UNITED STATES 2,190,859 APPARATUS roa some super METAL Henry E. Guerin, Beverly Hills, CaliL, assignmto Douglas Aircraft Company, Inc., Santa Monica, Calif., a corporation of Delaware Continuation of application April 18, 1936, Se-

rial No. 75,114.

Division of application September 9, 1935, Serial No.

dated September 39,696. Patent No. 22, 1936. Divided and this application January 26, 1939, Serial 1 Claim.

My invention relates to the art of forming sheet material into predetermined shape, and

relates particularly to an improved method and apparatus whereby sheet metal may be economically and expeditiously formed into desired shapes.

This application is a continuation of my co pending application entitled Method and apparatus for forming sheet metal, Serial No. 75,114, filed April 18, 1936, and is a division of my application entitled "Method and apparatus for cutting sheet metal, Serial No. 39,696, filed September 9, 1935, and which on September 22, 1936, matured into Patent No. 2,055,077.

Although my invention is useful wherever sheet metal must be formed, it is particularly useful in those arts and industries wherein relatively few shapes of the same size and configuration must be made. For example, in the airplane building industry it is necessary to employ metal members which are made from sheet duralumin. More particularly in the wings of an airplane there are members known as ribs which are of a certain shape and have flanges formed as a part thereof. The number of ribs of a given size and configuration required for a single airplane or for a number of airplanes is relatively small. If such ribs are made in accordance with standard practice of making dies and forming blocks, there is a considerable investment in such parts since it is well known that a very accurate dimensional relationship must be adhered to. Furthermore, in forming apparatus employing these parts it is necessary to very accurately and carefully install the die and forming blocks so that there will be accurate alignment of the parts in order that sheet metal may be formed into ribs which will be of proper configuration. It is an object of my invention to provide an apparatus wherein the cost of the parts for forming the sheet of metal is greatly reduced, and in which it is unnecessary to make companion forming and die parts which, even in their simplest form, involve a relatively large amount of labor and expense.

It is a further object of the invention to provide an apparatus of. the above character in wh ch, instead of relatively costly companion punch and die members, simple blocks or bodies are used for forming operations on sheet metal, and it is a further object to provide, for use with these blocks, a means for applying to the sheet metal, which is placed in cooperating relation to the blocks, a body of resilient or fiowable substance adapted to conform under pressure to the shape or contour of the blocks and to apply to the sheet metal ample pressure for performance of the forming operations to be made thereon.

It is a further object of the invention to provide a simple and novel press in which the forming blocks may be placed and used for performing the various operations on the sheet metal, without the necessity of securing these blocks or of aligning the same with cooperating die parts.

In my present invention the forming blocks may be cheaply made and may be immediately put into use for the purpose of manufacturin the desired sheet metal parts. These forming blocks are of such character that they may be machined from flat steel plate or may be formed by a casting or molding process, and are of such character that they may be laid upon the bed of the forming press without the need for securing elements or the exercise of skill as in the mounting for forming members and dies in ordinary forming presses.

It is a further object of the invention to provide an apparatus for forming parts from sheet metal, wherein the design of the manufactured parts will not be influenced to such a great extent as heretofore by experience in the making of forming members and dies for the parts to be formed. i

A further object of the invention is to provide an apparatus of the above character which will lend itself to the ready forming of beads or channels in parts, such as panels formed of sheet metal, so as to stiffen the same against buckling and vibration, this type of stiffening means being much less expensive than the riveting onto the panel or part of supplementary reinforcing parts, such as metal strips or angles. This is very important in the manufacture of parts which are to be used in the construction of airplanes, since in this form of construction parts having the same strength and stiffness as those originally reinforced by the application of stiffeners to the faces thereof can be now made much lighter so that a great saving in weight in the finished airplane is accomplished. In addition to lightening the structure, the facility with which complete metal parts are'formed from a single sheet of metal contributes to other savings in production, labor, and cost. The decrease in the number of parts, decrease in the amount of drafting formed parts. In the methods and apparatus in use at the present time it is necessary to take the time to set up a machine in order to form these one or more parts. This obviously greatly builds up the overhead and therefore makes the cost of a few parts relatively expensive.

It is one of the important objects of my present invention to provide an apparatus whereby formed parts may be very quickly made, since in my invention no prior special set-up of apparatus is required. In the preferred form of my invention it is possible to simultaneously by a single operation make one or more parts of a given configuration or to make one part of one configuration and at the same time make other parts of'a different configuration. It will therefore be seen that in my invention the overhead involved in making a single part is no greater per part than where a large number of identical parts are made.

It is a further object of my invention toprovide an apparatus which consists of a table member, a wall or body of fiowable material, and a forming member adapted to be placed between the table and the body, the forming member having a sheet of metal to be formed suitably positioned thereon, and means for confining the body of fiowable material, the forming member, and the sheet of metal in a closed or confined space wherein pressure is gradually applied so that the body of fiowable material causes the sheet of metal to conform to the configuration of the forming member.

It is another object of my invention to provide an apparatus for forming sheet metal wherein the sheet of metal is first gripped by a body of fiowable material so as to be positively held in the desired position on the forming block, and thereafter the body of fiowable material is acted upon in such a manner as to cause the sheet of metal to conform to the forming member, thus forming the sheet of metal into the desired shape.

It is a still further object of my invention to provide an apparatus of the character pointed out heretofore in which the forming block and the sheet of metal or the formed part are readily accessible when the body of fiowable material is in a relatively separated position. This is an important part of my invention since it makes it possible to very conveniently place the sheet of metal on the forming block or to remove the "formed piece from the forming block.

It is an important object of my invention to provide an apparatus wherein a number of shapes may be simultaneously formed by a single operation, these shapes being identical or different, and it being immaterial to the operation of the device whether there be but one shape formed or a plurality of shapes formed at a single operation.

My invention includes other objects and advantages which will be emphasized during the description of the preferred method and apparatus of my invention.

Referring to the drawings which illustrate a preferred form of apparatus of my invention:

Fig. 1 is a vertical sectional view through the apparatus.

Fig. 2 is a plan view of the table of the apparatus shown in Fig. 1 and illustrating the manner in which the various forming blocks may be placed on the table. I

Fig. 3 is a perspective view of a forming block incorporating the features of myinvention.

Fig. 4 .is a plan view of the forming bl shown in Fig. 3 and illustrating the manner in which the blank, that is, the sheet of metal to be formed, is placed on the forming block.

Fig. 5 is a section taken on the line 5-5 of Fig. 4 illustrating the means and manner in tion is commenced.

Fig. 8 is a fragmentary sectional view showing the relative positions of the parts when the blank has been gripped or engaged by the fiowable body so as to be securely held in place.

Fig. 9 is a view showing the relative positions of the parts when the blank is partially formed.

Fig. 10 is a view showing the positions of the various parts when the blank has been completely formed into the desired configuration or rib as illustrated in Fig. 6.

Referring to the drawings in detail; and particularly Figs. 1 and 2, the form of my invention shown herein comprises cooperating part and 2| which are adapted to be moved relatively together and apart under pressure to perform the forming operation of my invention. The member 20 may be considered as a table or support, and the member 2| may be termed a head" which moves relative to the table 20. It is immaterial to the invention whether the table 20 or the head 2| is the movable part, since all that is necessary is that the parts be capable of being moved together and apart, as will be explained. Adapted to be supported by the table 20 is a plurality of shaping blocks or forming blocks 22, 23, and 24. Although these blocks may be integrally formed with the table 20, in the preferred form of my invention and in order to obtain certain important advantages of my invention these forming blocks 22, 23, and 24 are separate from each 20, and during their the upper fiat surface forming blocks may be placed on the upper surface 25 of the table 20 as they are desired for use are merely laid upon use, and although they may be interlocked in a predetermined position, it is one of the features of my invention to have the forming blocks adjustable in position in order that they may be arranged in any desired positions on the table 20 so that when necessary a large amount of work may be performed by a single operation of the apparatus.

Secured to the lower face 26 of the head 2| is a flat layer or body 21 of a yieldable resilient or semi-fluid material which is best characterized by the terms rubbery, fluid-like or fiowable. In actual practice I have found that this wall or body 21 may be made from rubber or a rubber compound to achieve the desired results of my invention. I do not, however, wish to be limited to these particular materials- When the head 2! and the table 20 are moved relatively together the yieldable rubbery material of the wall 21 is forced against the forming blocks 22, 23, and 24 and against the exposed upper surface of the table 20, and when sufilcient pressure is applied the rubbery material conforms itself to the external surfaces of these blocks or during a forming operation to the blanks placed other and from the table 25 0f the table 20. These on the forming blocks, as will be pointed out shortly.

To constrain the body 21 from lateral expansion when it is under pressure, a peripheralwall 28 is provided, and which is preferably secured to and constitutes a part of the head 2|. It will be seen that this wall" projects downwardly aroundand below the body 21 so that prior to the time that any pressure is exerted on the body 21 the lower edges of the wall 28 have overlapped the side faces of the table 20, as shown by dotted lines 28a, thus forming a relatively closed space or confined space 30 in which is situated the body of rubber 21, the forming blocks 22, 23, and 24,

and also the blank or formed member, as will be described shortly.

In Fig. 3 I show a perspective view of the forming block 22 which is intended for use in forming a sheet of metal or blank into a metal rib 3|, such as is shown in Fig. 6, which is of a type used in the wing construction of an airplane. The forming block 22 comprises a flat body 32, such for example as tool steel, which body 32 may be cut from a flat plate. This body is provided with an external peripheral vertical face 33 which meets the upper horizontal flat face 34 of the bodyv 32 at an upwardly and outwardly disposed rounded corner or edge 35. The body is likewise provided with openings 33 defined by vertical walls 31 which meet with the upper face 34 of the body 32 so as to form rounded edges 38. If desired, the body 32 may be provided with corrugation or bead grooves 39 formed in the upper surface 34, these grooves being-employed to form beads in the rib formed thereon for reinforcing purposes. The forming block is provided with centralizing or aligning pins53 which project upwardly from the upper surface 34 and are useful in centralizing the blank on the forming block, as will be described later. I

As will be obvious from the foregoing, the forming block 22 may be very economically made, since itis merely cut from a flat plate, and the .openings 36 therein may be made to any desired shape without great additional cost over the cost of forming simple circular holes.- As shown in Fig. 3, these openings 36 may be oval or rectangular or a composition of oval and rectangular.

Referring to Figs. 4 and 5, the numeral 4| represents a blank which has been previously cut to desired size. This blank in the form of the invention illustrated consists of a sheet of duralumin which is the material extensively employed in airplane manufacture. This blank may be made in any suitable manner, such for example as is illustrated in my Patent No. 2,055,077

" referred to heretofore.

In Figs. 4 and 5 the dotted lines 42 represent the forming block 22. The blank 4| is provided with aligning openings 43 and is placed on the forming block with the aligning pins 53 extending through the openings 43. This initially aligns the blank 4| is proper position on the forming block. It will be seen that the blank has edges or flanges 44 which project outwardly beyond the wall 33 of the forming block and edges or flanges 45 which project inwardly beyond the walls 31 defining the openings 35. These extending portions or flanges 44 and 45 constitute the portions or parts of the blank which are forced downward to form flanges which are shown in Fig. 6, wherein the completed rib is illustrated. These flanges constitute an outer flange 48 which is integral with the upper flat wall 41 and flanges 48 defining openings 43, which the blanks properly installed on them may be arranged in any suitable position on the surface 25. Since the forming blocks are all independent of each other and independent of the table 20, this arrangement is possible. It is desirable, however, to separate the forming blocks at least a short distance from each other in order that there will be ample space around each of the forming blocks so that the body of flowable material 21 may surround the parts in order to perform the forming operation, as will be pointed out. It will be seen that there may be one or more forming blocks of the configuration of 22 or one or more of other configurations. It will therefore be seen that the apparatus and method are operable if a single rib is formed or if a plurality of ribs or other shapes are simultaneously formed.

The head 2| is then moved downward by any suitable apparatus (not shown), such for example as a hydraulic ram. This is effective in moving the head into the position shown by dotted.

lines 28a of Fig. l and forms the closed space 30. The body of rubber 21 is at this time in a position shown in Fig. 7 and is in a position to engage the blank 4|. Up to this point in the process no pressure has been applied to the blank. As the head continues to lower, the rubber body 21 will come into engagement with the blank 4|, as illustrated in Fig. 8. Prior to the time that the blank 4| is engaged by the body of flowable material 21 it is aligned on the forming block 22. Therefore, when the body 21 engages and pressurally grips the blank 4| this blank will be securely held against the upper face 34 of the forming block 22 in a proper position. It will be seen that at this time pressure is applied at the areas 49 which effectively grip the blank 4| and securely hold it against the upper face 34 of the forming block 22. It will be seen that at this I time the projecting edges of flanges 44 and the portions 50 which are above the grooves 39 and also the flanges 45 shown best in Fig. 4 are unsupported and that there is therefore a preponderance of pressure or force applied to these parts in a downward direction. I find it preferable to provide the flowable body 21 with a flat lower or exposed surface so that the blanks 4| will be squarely engaged and will not be displaced laterally, and I also prefer to arrange the height of the forming blocks so that the blanks will be simultaneously engaged.

After the forming blankhas been securely held in place, as explained in the preceding paragraph, the head 2| is moved further downward and the rubber body or body of flowable material 21 is further compressed and the parts will take the position shown in Fig. 9 which is one of the intermediate positions between those illustrated in Figs. '1 and 10. In view of the fact that the body of flowable material 21 is fully confined in the space 30, it cannot spread outward and will therefore be forceddownward around the parts as illustrated in Fig. 9, and because of the character of the flowable material a pressure is exerted substantially in all directions. It is, of

that of a liquid, but the characteristics of equal pressure in all directions are predominant in the body of flowable material. It will be seen that as this pressure is developed the flanges l4 and 45 are forced downward toward completely formed position and the portions 50 are forced part way into the grooves 39.

As the head is moved downward a greater distance, a greater pressure is applied and the body of flowable material 21 is placed under greater compression. Finally, the body of flowable material exerts sucha pressure on the blank 4| and completely surrounds the blank 4| and the forming block 22 on three sides and fills the openings 36, so as to completely form the blank into the desired shape. The relative positions of the parts at this time are shown in Fig. wherein the body of flowable material 21 is forced downwardly against the upper surfaces and inwardly against the side surfaces of the metal constituting the blank 4| but which has at this time been formed into the rib 3|, as illustrated in Fig. 6. It will be seen that when the parts are in this position the space 30 is substantially filled by a flowable material being compressed so as to substantially fully occupy all existing spaces and crevices in the space 30.

The next step in the process is to separate the head 2| and the table 20. This is done by raising the head 2|. The flowable body is preferably of such a nature that it will return to substantially its original contour, as shown in Fig, 1, and thus occupy a position wholly within the head 2| and exposing a substantially flat lower surface. It is one of the important features of the present inventionthat the-body of flowable material very readily disassociates itself from the formed part 3| and will be raised into the position shown in Fig. 1 or a higher position as desired, depending upon the amount of elevation of the head 2| so that the upper surface of the table 20 is readily accessible. The formed rib 3| is then removed from the forming block 22. This may be done without removing the formed block from the upper surface 25 of the table 20, or, if desired, the entire assembly may be removed and the parts disassembled elsewhere. This completes the performance of the process and a complete operation of the apparatus of my invention. Subsequent operations may be performed in the same manner as described.

From the foregoing description it will be seen that the process and apparatus are operable with one or more forming blocks in use. It is obvious that if only a forming block 22 were placed on the table 20, the blank ll would be formed into the rib 3|, as explained. It is further obvious that if a multiplicity of forming blocks and blanks were placed on the table 20 that the forming operations with relation to each would also be satisfactorily performed. A very important advantage of the invention, as pointed out in the statement of invention, is that if it is necessary in an emergency to form only a single part, such for example to form a single rib 3|, all that is necessary is to place the forming block 22 and the blank on the table 25 and operate the device. No particular alignment is required since any portion of the flowable body 21 is capable of engaging the blank and forming the blank into the desired shape in accordance with the method described and the method illustrated in Figs. 7 to 10 inclusive. This advantage of my invention is quite an important one, since it eliminates entirely all costs in connection with setting up an apparatus to perform the operation, as is required in those methods employing dies and forming blocks. This may readily be appreciated from the following example. If a machine is in operation forming certain parts and it is desired to have one or two parts of a different shape, it is necessary to remove the die and forming parts which are used in the previous operation and to install thedie and forming parts to make the shaped member which is desired. The forming part and die must be accurately aligned so that a properly shaped member may be produced. After the one or two shaped members have been produced, then the forming parts and die must i be removed and the previously installed ones reinstalled and aligned to continue the original operations which were interrupted. If this process is compared with the invention disclosed, described. and claimed herein, it will be seen that there is a large saving in cost from the standpoint of setting up the apparatus.

It will further be seen that there is a valuable advantage in a saving of time. In my method and apparatus disclosed herein it is possible to immediately produce one or more parts, since no special set-up of the apparatus is required.

It will also be seen from the foregoing description that the cost of the apparatus employed for forming the blank into the desired shape is much lower than in standardmethods which employ the forming part and the die which must be very accurately made and the dimensions of each must very closely correspond in order that the metal may be properly shaped without undue injury or stress in any portion of the metal. It will further be seen that it is very easy to ob tain odd or peculiar shapes which are extremely costly when made by the ordinary forming part and die method and apparatus. In my invention the only part which is specially formed is 'the forming block, and it is not necessary to make this forming block correspond in precise or minute dimensions to any-other part.

In the foregoing description I have disclosed and described a preferred form of method and apparatus of my invention. It should be understood, however, that various alterations and modifications may be made in them without departing from the spirit and scope of the invention. 'I therefore do not wish to be limited to the precise details herein disclosed but wish my protection to extend to all structures and methods coming within the spirit and scope of my invention as defined in the appended claim.

I claim as my invention:

In an apparatus for forming sheet metal articles, a table member having a substantially flat and non-yieldable supporting surface, a head member above said supporting surface movable toward and from said table member, means to move said head member, a depending flange carried by said head member and forming a pocket or recess, a body of resilient flowable material disposed in said recess and secured to said head member, the body having a substantially flat exposed surface extending in a plane parallel to that of the supporting surface, and a forming block removably resting on said supportingsurface and adapted to receive a sheet metal blank to be shaped thereon, said head member together with its attached flange and body of resilient flowable material when in inoperative position being well spaced from the supporting surface to allow ready access to the forming block and blank located on said supporting surface and rapid placement and removal therefrom, the flange being of substantially the same shape and size as the supporting surface so as to fit directly in telescoping relation ther ewith on relative movement of the head and supporting surface toward each other, the flange, flowable material, and non-yielding surface forming a hollow chamber when in telescopic engagement whereby when said table and said head member are 10 brought together under pressure said body of flowable material will be compressed and constrained against outward expansion by said flanges and head member and will first press said sheet metal blank against said forming block by engagement of said substantially flat exposed surface therewith and upon application of further pressure will shape said sheet metal blank around said forming block. 

